XIV] 



ANTHERIDIAL WALL 



293 



divisions tend, however, to be irregular. In Diacalpe sometimes two divisions 

 exist, but usually only one (Fig. 283, //, /): in Woodsia obtusa one is usually 

 present (Fig. 283, G\ but undivided cap-cells have been seen to occur; a 

 condition which is described as usual for W. ilvensis. This is the state which 



Fig. i%i. Segmentation of antheridia in Ferns and in Equisetiim. 

 a = type of Trichomanes, and of Leptosporangiates generally; 

 i5 = type of Osmimda (Campbell, Mosses and Ferns, Fig. 195, C) ; 

 f = type of Marattiaceae and Ophioglossaceae; d, e, f=Eqiiisetiiin, 

 after von Goebel; ^=antheridium on end of filament; ^=vie\v of 

 the same from above; /=the antheridium sunk in the massive 

 thallus. (See von Goebel, Organographie, 2nd Ed. Fig. 910.) 



Fig. 283. Antheridia of various Ferns seen in surface view: the operculum is shaded. The 

 scale is not uniform. They show a progressive simplification of the segmentations of the 

 cap-cell. In F — /, the inner circle represents the cap-cell. In the Polypodiaceae this is 

 not divided at all, but comes away bodily as the operculum. Compare Fig. 277. A = Botry- 

 chium Luuaria, after Bruchmann ; B = Angiopteris, after Campbell ; C= Katdfussia, after 

 Campbell; D = Danaea, after Campbell; E^Osiniinda, after Heine; F= Trichomanes, 

 after von Goebel; G=M^oods/a obtusa, after Schlumberger ; H, I = Diacalpe, after 

 Schlumberger. 



is general for the " Polypodiaceous " Ferns, in which the cap-cell develops 

 without segmentation into the single opercular cell. These steps of 

 progressive simplification express in details of wall-structure a progression 

 roughly parallel with the diminution in number of the spermatocytes, as 



